Vacations are important. Done right, they can lead to fresh perspectives, creative insights and reduced stress levels. There's a strong case to be made that taking the time to unplug is not only beneficial for our mental and physical health, but may boost the health of our careers as well.

Unfortunately, according to a new survey by rate-your-company startup Glassdoor, most of us aren't taking very many of them.

The survey found that the average U.S. employee only took 51 percent of their eligible vacation/paid time off in the last year. Fifteen percent didn't take off any time at all, while a mere 25 percent of employees reported using all of their allocated vacation days. And even when we're on vacation, the survey revealed, most of us don't unplug: Sixty-one percent of employees who took time off admit that they did some work while out of the office.

It's important for CEOs and managers to encourage employees to use their vacation days, says Scott Dobroski, a senior manager at Glassdoor. "Vacation helps employees avoid burnout," he says. "Taking time off can make them both more productive and more satisfied when they return to work, which translates into higher retention rates that can save a company thousands of dollars."

Those in senior positions should lead by example, recommends Dobroski. If a CEO is not taking any paid time off – or if she goes on "vacation" but is still accessible 24/7 – she is making a clear statement about how employees should treat their own vacation time.

To empower and motivate employees. Leaving the office for a week or two forces you to shift major responsibilities to your employees. "I have found that when entrepreneurs empower their staff, they are more productive when their boss is gone," says Brian Miller, the chief operating officer of AdviCoach, a provider of business coaching to small companies. To instill confidence in your employees (and for your own peace of mind), begin delegating tasks while you're still in the office. That way, be it sales calls or stocking inventory, employees learn the ropes before they fly solo. Read More: 5 Steps to a Stress Free Summer Vacation

To get inspired. Richard Branson is a strong proponent of getting away from it all. "The places you go and the new people you meet can inspire you in unexpected ways," he writes. "As an entrepreneur or business leader, if you didn't come back from your vacation with some ideas about how to shake things up, it's time to consider making some changes." Read More: Richard Branson on How to Take an Inspirational Vacation

To sniff out dysfunction. If a majority of your employees are not using any of their vacation days, that could be a red-flag says Andrea Herran, the founder of Focus HR, a human resource consultancy. Is there some sort of dysfunction there? Is there a problem with the team? The employees may be overwhelmed or even staying put to cover up wrongdoing. "Employees need to get away and recharge. If they're not doing so, something could be seriously wrong and it could be hurting your company," she says. Read More: Should You Give Your Employees Unlimited Vacation Time?

To gain a new perspective. For Crosby Noricks, a fashion marketing strategist and founder of PR Couture, time off "actually fuels my creativity and gives my brain space to come up with better ideas, solutions to problems and efficiencies that I can't always access if I am operating at a furious pace.” Read More: A Healthy Work/Life Balance Is No Unicorn

To disengage. Taking a break is often seen as the lazy man's solution, but that may be the wrong way to look at it, says Bonnie Hayden Cheng, a PhD student at the University of Toronto. Recently Cheng co-authored a study which examined a group of university students juggling work, family and academic responsibilities. Participants who practiced cognitive disengagement by actively taking their minds off their troubles and onto something completely unrelated were better able to manage the tasks at hand than those who tried to push through without breaking.

That may sound counterproductive, but "Actively taking your mind off the problems at hand actually helps manage multiple role responsibilities and leads to increased levels of [work] satisfaction," says Cheng. Read More: Why Entrepreneurs Need More 'Me' Time